Place the potatoes in a large pot and add enough water to cover them by about an inch. Allow the potatoes to boil for 10 to 15 minutes.

When the potatoes are just tender and easily pierced with a fork, remove the pot from the heat and drain them well.
Allow the boiled potatoes to cool slightly so they can be easily handled.

Peel the potatoes, cube them into 1-inch bite-sized pieces, and place into a large mixing bowl. (Tip: Do not allow the potatoes to chill completely before peeling and cubing; they absorb the flavors of the salad best when they are mixed with the other ingredients while still warm.)

Peel the hard-boiled eggs and slice them in half.

Place the yolks into a medium-sized mixing bowl and set aside.

Roughly chop the egg whites and add them to the bowl with the potatoes.

Mash the egg yolks. (Tip: A simple dinner fork is your best friend for this job.)

Add the yogurt, mayo, mustard and vinegar to the mashed egg yolks and whisk with a fork until smooth and creamy.

Season with salt and pepper to taste.

Add the egg yolk mixture to the bowl of potatoes and chopped egg whites and gently stir to combine.